Home  About us  Contact
 

Multiple Emulsions (multiple + emulsion)

Distribution by Scientific Domains
Chemistry56%

Selected Abstracts

MICROSTRUCTURAL AND RHEOLOGICAL PROPERTIES OF LOW-FAT STIRRED YOGHURTS MADE WITH SKIM MILK AND MULTIPLE EMULSIONS

JOURNAL OF TEXTURE STUDIES, Issue 6 2009
C. LOBATO-CALLEROS
ABSTRACT This article focuses on the study of the dynamic rheological and structural properties developed in low-fat stirred yoghurts made with skim milk and multiple emulsions stabilized with carboxymethylcellulose (SYCMC) or amidated low methoxy pectin (SYALMP), in comparison with a full milk-fat stirred yoghurt control (SYMF). The SYALMP yoghurt exhibited greatest Tan,after 14 days of storage than the SYMF and SYCMC yoghurts. The SYALMP yoghurt presented the highest lacunarity value and was characterized by a structure composed of highly clusterized casein aggregates. In contrast, the SYCMC and SYMF yoghurts displayed lower lacunarity values and structures characterized by smaller casein clusters. Lower Tan,values were associated with lower lacunarity values. PRACTICAL APPLICATIONS Limited work has been done on stirred and set-style yoghurts, cheeses and, in general, dairy products, where milk-fat globules are substituted by skim milk combined with multiple emulsions containing polyunsaturated vegetable oils. As a result of this, multicomponent gels formation occurs (made up by milk proteins, polyunsaturated vegetable oils, emulsifiers, hydrocolloids and many possible other ingredients), which give rise to completely different structural arrangements that may display comparable mechanical-sensory properties with those exhibited by their full milk-fat counterparts, paving the way for the development of new healthier foods sensory and texturally acceptable to consumers. [source]

Microfluidic Mass-Transfer Control for the Simple Formation of Complex Multiple Emulsions,

ANGEWANDTE CHEMIE, Issue 39 2009
Chun-Xia Zhao Dr.
Mehr als eine einfache Emulsion: Bei einer direkten Methode zur Umwandlung einer einfachen Emulsion in Mehrfachemulsionen in einem T-förmigen Mikrofluidiksystem wird Wasser als Cosolvens in Öl eingebracht. Am Kreuzungspunkt bildet sich zunächst eine einfache Emulsion, anschließend entsteht auf autokatalytischem Weg dann eine Mehrfachemulsion, indem das Cosolvens in die kontinuierliche Phase eindringt. [source]

Regimes of Multiple Emulsions of W1/O/W2 and O1/W/O2 Type in the Continuous Couette-Taylor Flow Contactor

CHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 1 2010
E. Dluska
Abstract The flow regimes of multiple emulsions in the continuous Couette-Taylor flow (CTF) contactor and characterization of the dispersion state are reported. The proposed method of multiple emulsion preparation is a one-step procedure on the contrary to the classical two-step procedure. The effect of operating parameters in the CTF contactor on multiple emulsion appearance, structure (drop size and packing), and rheological behavior is discussed. The key factors affecting multiple emulsion preparation in the CTF apparatus were the phases ratio, the rotational flow, and an annular gap width. The influence of an axial flow was more significant in the range of small rotational rates. The operating conditions were optimized to find the best characteristic multiple emulsions (largest interfacial area). The paper presents the same exemplary data of using W1/O/W2 emulsions as emulsion liquid membranes (ELMs) in the extraction process and O1/W/O2 for control active agent (drug) release. [source]

Amphiphilic polyelectrolyte for stabilization of multiple emulsions,

POLYMER INTERNATIONAL, Issue 4 2003
Fanny Michaut
Abstract Multiple emulsions are complex thermodynamically unstable systems where both types of emulsion coexist. We investigated the stability behaviour of water-in-oil-in-water (W/O/W) emulsions formulated with a hydrophobically modified poly(sodium acrylate) emulsifier at the outer interface and a monomeric surfactant (span 80) at the inner interface. Their stability was tested through release kinetics of a marker (NaCl) initially encapsulated in the aqueous droplets, and by rheology. Slow release rates and remarkably long shelf-life were obtained compared to typical multiple emulsions stabilized by two commonly used surfactants (span 80 and tween 20). In addition, we prepared stable highly concentrated multiple emulsions. Their rheological behaviour indicated that the internal interface was essentially covered with span 80. Thus, transportation of the polymer across the oil phase is limited, which in turn explains, at least partially, the stability improvement in the presence of the polymeric emulsifier. Finally, the long lifetime of the emulsions allowed study by diffusing wave spectroscopy of the interactions between the droplets and the globule surface which are important for understanding the destruction mechanisms of multiple emulsions. © 2003 Society of Chemical Industry [source]

The characterization of the semi-solid W/O/W emulsions with low concentrations of the primary polymeric emulsifier

INTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 2 2005
D. Vasiljevic
Synopsis Semi-solid multiple W/O/W emulsions with low concentrations (0.8, 1.6 and 2.4% w/w) of lipophilic polymeric primary emulsifier PEG-30-dipolyhydroxystearate (PDHS) have been formulated. Both emulsions, primary and multiple, were prepared with high content of inner phase (,1 = ,2 = 0.8). All the formulations differ only in the lipophilic emulsifier concentration. Evaluating several parameters such as macroscopic and microscopic aspect, droplet size, accelerated stability under centrifugation and flow and oscillatory rheological behaviour, assessed the multiple systems. It is possible to formulate the semi-solid W/O/W multiple emulsions with low concentrations of PDHS as the primary emulsifier. It appeared that the highest long-term stable multiple emulsion with the lowest droplet size, the highest apparent viscosity and highest elastic characteristic, was the sample with the highest concentration (2.4% w/w) of the primary emulsifier. Résumé Les émulsions H/L/H semi-solides ont été formulées avec les concentrations basses (0.8, 1.6 et 2.4% m/m) de l'émulsifiant lipophile polymèrique PEG-30-dipolyhydroxystearate. Les émulsions simples et multiples ont été préparées avec la teneur élevée en phase intérieure (,1 = ,2 = 0.8). La teneur en émulsifiant lipophile était la seule différence entre ces formulations. L'aspect macroscopique et microscopique, la taille de globules, la stabilité physique déterminée par le test de centrifugation ainsi que le comportement rhéologique (rhéologie d'écoulement et oscillatoire) ont permis l'évaluation des émulsions multiples. Il est possible de formuler les émulsions H/L/H semi-solides multiples avec les concentrations basses de PEG-30-dipolyhydroxystearate comme émulsifiant primaire. Il a été découvert que l'émulsion H/L/H multiple avec le plus grand pourcentage (2.4% m/m) de l'émulsifiant primaire a le diamètre de globule le plus petit, la plus grande viscosité apparente et le plus grand module élastique ainsi que la plus longue stabilité. [source]

Tea tree oil concentration in follicular casts after topical delivery: Determination by high-performance thin layer chromatography using a perfused bovine udder model

JOURNAL OF PHARMACEUTICAL SCIENCES, Issue 2 2005
S.S. Biju
Abstract Tea tree oil, a popular antimicrobial agent is recommended for the treatment of acne vulgaris, a disease of the pilosebaceous unit. Tea tree oil formulations (colloidal bed, microemulsion, multiple emulsion, and liposomal dispersion containing 5% w/w tea tree oil) were applied to bovine udder skin. The follicular uptake of tea tree oil upon application was determined by a cyanoacrylate method. Tea tree oil was determined by quantifying terpinen-4-ol content using high-performance thin layer chromatography. The accumulation of tea tree oil in the follicular casts was 0.43,±,0.01, 0.41,±,0.009, 0.21,±,0.006, and 0.16,±,0.005 percentage by weight (milligram oil/gram of sebum plug) for microemulsion, liposomal dispersion, multiple emulsion, and colloidal bed, respectively. This is the first study of its kind to quantify tea tree oil concentration in the follicles. © 2004 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 94:240,245, 2005 [source]

A very promising new glucolipidic surfactant: LipowheatTM

INTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 6 2005
A. Djedour
Synopsis LipowheatTM is an entirely biodegradable 100% natural active ingredient, extracted from non-transgenic wheat. Thanks to its very interesting properties, it can integrate the composition of most cosmetic and pharmaceutical products. The aim of this work was first to realize a large range of stable simple or multiple emulsions, in order to determine and evaluate the ability of a new glucolipidic surfactant LipowheatTM to form and stabilize emulsions. The rheological properties of these emulsions were tested during a 30-day storage period at three different storage conditions (cold, room temperature and at 40°C). In addition to dynamic and static rheological tests, droplet size distribution of the cream was also determined. Furthermore, a stable simple emulsion was selected to realize percutaneous absorption and evaluate the properties of LipowheatTM. Résumé Ce travail a pour objectif de mettre à jour et d'évaluer les propriètés émulsionnantes d'un nouveau tensioactif de nature glucolipidique, connu jusqu'alors pour ses propriétés actives en cosmétologie: le LipowheatTM. Cette étude comporte plusieurs parties distinctes: 1) Formulation d'émulsions simples L/H et/ou H/L et multiples H/L/H stabilisèes par du LipowheatTM, avec des huiles variant par leur origine (naturelle ou synthétique) ainsi que par leur polarité. 2) Caractérisation rhéologique, granulométrique, et conductimétrique de ces émulsions après les avoir soumises pendant 30 jours à des conditions de vieillissement accéléré (conservation à température ambiante, à +4°C et +40°C) et ce, afin d'en retenir les plus stables pour la suite de l'étude. 3) Enfin, dans une dernière phase, les propriètés de ces crèmes dans le domaine de la libération dermopharmaceutique seront évaluées lors d'études in vitro. [source]

The characterization of the semi-solid W/O/W emulsions with low concentrations of the primary polymeric emulsifier

INTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 2 2005
D. Vasiljevic
Synopsis Semi-solid multiple W/O/W emulsions with low concentrations (0.8, 1.6 and 2.4% w/w) of lipophilic polymeric primary emulsifier PEG-30-dipolyhydroxystearate (PDHS) have been formulated. Both emulsions, primary and multiple, were prepared with high content of inner phase (,1 = ,2 = 0.8). All the formulations differ only in the lipophilic emulsifier concentration. Evaluating several parameters such as macroscopic and microscopic aspect, droplet size, accelerated stability under centrifugation and flow and oscillatory rheological behaviour, assessed the multiple systems. It is possible to formulate the semi-solid W/O/W multiple emulsions with low concentrations of PDHS as the primary emulsifier. It appeared that the highest long-term stable multiple emulsion with the lowest droplet size, the highest apparent viscosity and highest elastic characteristic, was the sample with the highest concentration (2.4% w/w) of the primary emulsifier. Résumé Les émulsions H/L/H semi-solides ont été formulées avec les concentrations basses (0.8, 1.6 et 2.4% m/m) de l'émulsifiant lipophile polymèrique PEG-30-dipolyhydroxystearate. Les émulsions simples et multiples ont été préparées avec la teneur élevée en phase intérieure (,1 = ,2 = 0.8). La teneur en émulsifiant lipophile était la seule différence entre ces formulations. L'aspect macroscopique et microscopique, la taille de globules, la stabilité physique déterminée par le test de centrifugation ainsi que le comportement rhéologique (rhéologie d'écoulement et oscillatoire) ont permis l'évaluation des émulsions multiples. Il est possible de formuler les émulsions H/L/H semi-solides multiples avec les concentrations basses de PEG-30-dipolyhydroxystearate comme émulsifiant primaire. Il a été découvert que l'émulsion H/L/H multiple avec le plus grand pourcentage (2.4% m/m) de l'émulsifiant primaire a le diamètre de globule le plus petit, la plus grande viscosité apparente et le plus grand module élastique ainsi que la plus longue stabilité. [source]

Emulsion-Based Delivery Systems for Lipophilic Bioactive Components

JOURNAL OF FOOD SCIENCE, Issue 8 2007
D.J. McClements
ABSTRACT:, There is a pressing need for edible delivery systems to encapsulate, protect, and release bioactive lipids within the food, medical, and pharmaceutical industries. The fact that these delivery systems must be edible puts constraints on the type of ingredients and processing operations that can be used to create them. Emulsion technology is particularly suited for the design and fabrication of delivery systems for encapsulating bioactive lipids. This review provides a brief overview of the major bioactive lipids that need to be delivered within the food industry (for example, ,-3 fatty acids, carotenoids, and phytosterols), highlighting the main challenges to their current incorporation into foods. We then provide an overview of a number of emulsion-based technologies that could be used as edible delivery systems by the food and other industries, including conventional emulsions, multiple emulsions, multilayer emulsions, solid lipid particles, and filled hydrogel particles. Each of these delivery systems could be produced from food-grade (GRAS) ingredients (for example, lipids, proteins, polysaccharides, surfactants, and minerals) using simple processing operations (for example, mixing, homogenizing, and thermal processing). For each type of delivery system, we describe its structure, preparation, advantages, limitations, and potential applications. This knowledge can be used to facilitate the selection of the most appropriate emulsion-based delivery system for specific applications. [source]

Microencapsulation by Spray Drying of Multiple Emulsions Containing Carotenoids

JOURNAL OF FOOD SCIENCE, Issue 7 2004
M.E. Rodríduez-Huezo
ABSTRACT: Water-in-oil-in-water (W1/O/W2) multiple emulsions with 25% and 35% solids contents were spray-dried producing microcapsules with 3.9:1, 2.6:1, and 1.4:1 biopolymers blend to primary emulsion ratios and 0.25% (w/w) theoretical carotenoids concentration. Microcapsules with better morphology, encapsulation efficiency, and larger particle size were those obtained from higher biopolymers blend to primary emulsion ratios and solids content, but showed relatively higher carotenoids degradation kinetics than microcapsules made with lower biopolymers blend to primary emulsion ratios and solids content, which exhibited poorer morphology, encapsulation efficiency, and smaller particle size. Microcapsules stored at different water activities showed maximum carotenoids degradation at a water activity (aw) of 0.628, with lower carotenoids degradation occurring at lower or higher aw. [source]

MICROSTRUCTURAL AND RHEOLOGICAL PROPERTIES OF LOW-FAT STIRRED YOGHURTS MADE WITH SKIM MILK AND MULTIPLE EMULSIONS

JOURNAL OF TEXTURE STUDIES, Issue 6 2009
C. LOBATO-CALLEROS
ABSTRACT This article focuses on the study of the dynamic rheological and structural properties developed in low-fat stirred yoghurts made with skim milk and multiple emulsions stabilized with carboxymethylcellulose (SYCMC) or amidated low methoxy pectin (SYALMP), in comparison with a full milk-fat stirred yoghurt control (SYMF). The SYALMP yoghurt exhibited greatest Tan,after 14 days of storage than the SYMF and SYCMC yoghurts. The SYALMP yoghurt presented the highest lacunarity value and was characterized by a structure composed of highly clusterized casein aggregates. In contrast, the SYCMC and SYMF yoghurts displayed lower lacunarity values and structures characterized by smaller casein clusters. Lower Tan,values were associated with lower lacunarity values. PRACTICAL APPLICATIONS Limited work has been done on stirred and set-style yoghurts, cheeses and, in general, dairy products, where milk-fat globules are substituted by skim milk combined with multiple emulsions containing polyunsaturated vegetable oils. As a result of this, multicomponent gels formation occurs (made up by milk proteins, polyunsaturated vegetable oils, emulsifiers, hydrocolloids and many possible other ingredients), which give rise to completely different structural arrangements that may display comparable mechanical-sensory properties with those exhibited by their full milk-fat counterparts, paving the way for the development of new healthier foods sensory and texturally acceptable to consumers. [source]

Amphiphilic polyelectrolyte for stabilization of multiple emulsions,

POLYMER INTERNATIONAL, Issue 4 2003
Fanny Michaut
Abstract Multiple emulsions are complex thermodynamically unstable systems where both types of emulsion coexist. We investigated the stability behaviour of water-in-oil-in-water (W/O/W) emulsions formulated with a hydrophobically modified poly(sodium acrylate) emulsifier at the outer interface and a monomeric surfactant (span 80) at the inner interface. Their stability was tested through release kinetics of a marker (NaCl) initially encapsulated in the aqueous droplets, and by rheology. Slow release rates and remarkably long shelf-life were obtained compared to typical multiple emulsions stabilized by two commonly used surfactants (span 80 and tween 20). In addition, we prepared stable highly concentrated multiple emulsions. Their rheological behaviour indicated that the internal interface was essentially covered with span 80. Thus, transportation of the polymer across the oil phase is limited, which in turn explains, at least partially, the stability improvement in the presence of the polymeric emulsifier. Finally, the long lifetime of the emulsions allowed study by diffusing wave spectroscopy of the interactions between the droplets and the globule surface which are important for understanding the destruction mechanisms of multiple emulsions. © 2003 Society of Chemical Industry [source]

Regimes of Multiple Emulsions of W1/O/W2 and O1/W/O2 Type in the Continuous Couette-Taylor Flow Contactor

CHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 1 2010
E. Dluska
Abstract The flow regimes of multiple emulsions in the continuous Couette-Taylor flow (CTF) contactor and characterization of the dispersion state are reported. The proposed method of multiple emulsion preparation is a one-step procedure on the contrary to the classical two-step procedure. The effect of operating parameters in the CTF contactor on multiple emulsion appearance, structure (drop size and packing), and rheological behavior is discussed. The key factors affecting multiple emulsion preparation in the CTF apparatus were the phases ratio, the rotational flow, and an annular gap width. The influence of an axial flow was more significant in the range of small rotational rates. The operating conditions were optimized to find the best characteristic multiple emulsions (largest interfacial area). The paper presents the same exemplary data of using W1/O/W2 emulsions as emulsion liquid membranes (ELMs) in the extraction process and O1/W/O2 for control active agent (drug) release. [source]